XP and Windows 7 should (in theory) work together in a peer to peer LAN. Having stated that the real truth is that Windows has and always will be a pain in the neck when using a mix of different OS versions. Somewhere deep in the bowels of the windows networking code there are flaws that rear their ugly head when linking older versions of Windows with a newer version of Windows. It was true when linking Windows 98se to XP Pro, XP Pro to Vista, and now I just hit the TCP/IP wall with XP Pro SP3 to Windows 7 Home Premium. It has always been that the TCP/IP protocol that is built into all versions of Windows (from Windows 3.1 on) has never worked well with peer to peer networking. I won't go into and details because I could write volumes about what the problems are so I'll try be as brief as possible.

1. Always make sure the XP and Windows 7 computers have a password for the user name you are logging in with. Windows XP Pro can be set up to network in what is called "anonymous" login mode but that leaves some big security problems that can (and should) be avoided by making sure all computers in the network have login passwords. If you have a single user name on your computers and don't want to have to type in the password every time you boot XP or Windows 7 (you just want to boot right to the desktop) then go to a command prompt and type "control userpasswords2". This will run a simple utility "User Accounts" that has a check box at the top stating "Users must enter a user name and password to use this computer". Uncheck this, click OK and another window pops up asking you to type in a user name and password. Once you do that every time you boot XP, Vista, or Windows 7 (thank god that Microsoft didn't take it out of 7) you will automatically log in with that user name and password.

2. Always use 1 word user names. Some of the workarounds I've had to use require typing in commands from the DOS .. err .. Command prompt and since spaces in usernames don't work there having a single user name (or at least use the _ character instead of the space) will allow these commands (such as NET USE) to work when the "Network Places" method of navigating to the shared computer and finding the shared folder to map a drive letter to doesn't work. I ran into that exact problem yesterday trying to get a Windows XP Pro SP3 computer to map a drive letter to a share folder on a Windows 7 Home Premium computer so Microsoft hasn't fixed this yet.

3. As always make sure all computers have the same Workgroup name. It may seem like a trivial thing but a simple oversight on this will cause you big headaches so double check that each computer (XP and Windows 7) all have the same Workgroup name. I've always run into a failure to see other computers in the network if the workgroup names are different so pick a Workgroup name and set it on all computers in your network.

4-A. On the computer you are sharing the hard drive you will need to add the user names and passwords to be able to auto log in from the other computer. IF XP is the "server" then just go to the control panel, go into "Administrative Tools", and pick "Computer Management". In the Computer Management tool double click on the "Local Users and Groups" to expand it, then click on "Users" to get the current list of user names on the right. From here you can right click on either the "Users" in the left column or right click in the empty white space on the right to get a menu that has the "Add User" choice at the top so you can create user names and passwords for them. When done don't forget to go into the "Groups" choice and add the new users to the appropriate group (such as Administrators if that user needs full permissions).

4-B. WARNING !!! If you are going to want to use the Windows 7 Home Premium computer as the server and have XP Pro workstations then you are going to be in for a rude awakening. Microsoft (in their infinite wisdom... err... stupidity) has removed the "Local Users and Groups" out of all Home versions of Windows 7. This means there is no Group Policy Editor (gpedit.msc) so there is no easy way to add user names and passwords. It seams that Windows 7 should magically see the other XP Pro computers when you are "sharing" out a folder and adding the user names that are allowed access to it. This is another "In theory this should work" issue that is causing me big problems such as not seeing the XP computer because nothing on it is being shared so the "NET VIEW" command doesn't list these computers and when typing in the username Windows 7 states that it can't find the user so it refuses to add it to the share list. If anyone has tried to copy the "Microsoft Management Console" DLL file from a Windows 7 Pro or Ultimate version to Windows 7 Home Premium and get it to work I'd love to here from you. That trick worked with XP Home but I don't have a computer running either of these versions of Windows 7 yet so I haven't tried it myself.

5. Here's where the hair pulling can start so be prepared to get you hands dirty if the TCP/IP protocol fails to work properly. Normally after making sure the workgroup, user names, and passwords are all correct you should be able to go to "Network Places" and navigate down through "Entire Network", "Microsoft Windows Network". your Workgroup name, and see a list computers that have a folder(s) shared on them so you can then right click on the share, choose "Map Network Drive", pick the drive letter, and you're done. If in fact you do get this to work then HURRAY for you. You are indeed done and no hair pulling or gnashing of teeth is required. If you aren't one of the fortunate ones then network life just got a lot harder (I 'm not a "fortunate one"). I won't go into all the nitty gritty details (if you ask me nicely I will though) but the short answer to this is that there are still weird SNMP bugs in the Windows OS when using TCP/IP as the communication protocol in a mixed Windows OS environment. Microsoft always insists that this is all you need but I live in the "real" world and when all too often peer to peer network communication fails with the TCP/IP protocol I have to resort to adding in a 2nd network protocol. I just went through this on 11-27-09 when XP Pro always came back with a 1326 error even though I had everything set correctly on the Windows 7 Home Premium computer with the shared folder. Windows 7 did correctly see the XP Pro computer (it had a shared printer) so the XP user name was correctly added to the share list so all was good there but XP stubbornly refused to connect properly to the Windows 7 shared folder. I've had this problem too many times with XP and Vista so at least I knew what I had to do. I needed to add the IPX/SPX protocol. Since this is not in Windows 7 anymore I had to Google and find a link to download the Vista IPX/SPX protocol and add it but at least it can be found and the Vista IPX/SPX version works with Windows 7. Again if you need help here ask and I'll provide details. Anyway, after the IPX/SPX protocol is installed into XP and Windows 7 Home Premium the XP Pro computer can log into the Windows 7 computer successfully and the mapped drive function finally works. One would think that after 5 versions of Windows (98, 2000, XP, Vista, Windows 7) that this shouldn't be hard to do but the fact is that Windows has had so many programmers coding it and so many programmers have come and gone and Windows has been patched so many times that it's a wonder it works at all.

To anyone reading this I'd love to hear if you have any easier and simpler ways to use Windows 7 Home Premium as a server (and please no comments about why I shouldn't be using Home Premium at all as a server).

I've picked up an issue on customers 2 PC's, maybe someone can be so kind as to test this for me?

Windows XP has shared folder, Windows 7 has mapped drive to that shared folder.
The issue comes up with opening a file on that mapped drive in Word 2007 on the Win7 machine. When you save it the first time it's fine, subsequent to that it just falls over if you try save again. No errors given, just Windows in and endless loop and
Program not responding.

There is Norton on the XP machine but I don't want to uninstall just because it has a bad reputation.

I have this situation exactly, Windows 7 Ultimate with any Version of Windows XP. in fact i should say i only found a conflict and problem connect two computers with WINDOWS XP Professional SP2 and WINDOWS XP Home Edition SP1 in about 4 years ago. If you
try Windows 7 Ultimate, I'm Sure but about another versions i'm not sure.

I think that there should be no problem if the PC with Windows 7 will be hosting, because Windows 7 will recognize the PCs w. Windows XP. But if you will host with a Windows XP PC and connect a Windows 7 PC then I think that the Windows XP PC will not
be able to recognise the Windows 7 PC.

I seem to be one of the unfortunt ones and i really need to map a windows 7 drive(host) onto one of my window xp machines(client)....so could you please go over installing the ipx/spx protocol for windows 7x64....pretty please....pretty
please with sugar on top and a cherry.

I have just gone through some hair-pulling trying to access a Windows 7 shared drive from a Windows XP home computer. I had used the same (netbook) to access a desktop running Windows XP professional so I knew how to do it in the general sense.

First, if you have a firewall such as ZoneAlarm you must therein permit the other computer, either by IP address or by computer name, in each case.

Second, you share the drive on Windows 7 by going my computer/ {right click} drive / share with / advanced sharing /advanced sharing / share this folder (check box) settings and /permissions where you allow full (readwriteupdate) access. Remember to click
Apply every time before saying OK or close.

Third, you find Internet Properties / Security on Windows 7. Control panel / Internet Options brings up Internet Properties. Click Security, pick a zone (Trusted Sites, say) and add the IP address (or computer name, I suppose) of the XP machine. This was
the step I could not find except by blundering about .... so if you're stuck as I was you now can get this to work.

Fourth, on the XP machine get a command prompt (cmd.exe) and therein type

net use z: \\nameofwindows7computer\shareletter

shareletter was suggested by Windows 7 sharing dialog. Generally it is the drive letter without the colon.

You may be prompted for a userid and again for a password. A Userid that you can log on to on Windows 7 (the server) machine, followed by its password on Windows 7, should be supplied here. z: is the drive letter you want the
shared drive to be used as on Windows XP.

You can put the above commands into a .bat file .

Oddly enough, sharing a second drive with a comparable command does not ask for userid nor password. I am not sure why this is, but it has been consistent.

I do believe I had told the Windows 7 machine to forget about the sharing wizard; this is in Folder Options.You may not need this step.

I had already put both machines in the same WORKGROUP name. I am pretty sure you do need this step.

That seems to be it. I have it working.

Before you do this, try setting the firewalls as above (add each other as trusted IP addresses or sites) and then doing a command prompt

ping computername

(in both directions) to make sure the connection really is there. If you can't ping, you for sure won't be able to share.

good luck.

You will note that I did not add any protocols or special code to Windows 7. Since my machine is a new Acer I suspect its Windows 7 is pretty much vanilla, except for the gratuitous hotkey utility and games. I suspect what I did should
work for others.

Thanks for posting your article outlining the issues of Windows XP working in peer-to-peer networking. I read it with much interest. I don't really know how this forum works or if you will get this only if you happen to login again or if you
will be notified. But I have a couple of followup questions. I have a product which is well suited for small peer-to-peer networks where the office is not really big enough for a full sized server. I have experience with XP Pro to XP pro
p2p nets. But as yet no experience with Window 7 to XP. Before I read your article I was of the opinion it just wouldn't work. Unfortunately, perhaps, XP going away makes Win7-2-Win XP more of a necessity for me at least. From
your writing I am a wee bit dissuaded by my previous believes and that by using strict practices you suggest, it might just work. I got a sense from your writing you are actually using the configuration in a full time functioning environment, true?
Your focus was Windows 7 Home Premium, is the problems still with the configuration if you use Window 7 professional and Ultimate? What about Win 7 peer2peer to Win 7 environments, will that work reliably. Any specifics along those
lines I should know? Thank you very much for any input you could/will share. I am putting my email in because I am not sure I can navigate back to this thread. Bill Shaw...billyntilly@yahoo.com